Dry cell



C. W. HAZELET'T.

- DRY CELL. APPLICATION FILED MAY 9.1919.

Patented Feb. 24, 1920.

A TTORNE UNITED STATES PATENT OFFICE.

CLARENCE W. HAZELETT, OF LAKEWOOD, OHIO, ASSIGN'OR TO NATIONAL CARBON iI COMPANY,INC., A CORPORATION OF NEW YORK.

. DRY CELL.

To all whom it may concern..-

Be it known that I, CLARENCE W. HAZE- LETT, a citizen of the UnitedStates, residing at Lakewood, in the county of Cuyahoga and State ofOhio, have invented a certain new and useful Improvement in Dry Cells,of which the following is a full, clear, and exact description.

This invention relates to dry cells.

It is well known that dry cells are made from zinc cans which contain anelectrolyte mix tamped around a central carbon electrode with a paper orother bibulous lining between themix and the can. When paper is used asa bibulous lining it is the usual custom to use a lining that isconsiderably longer than the compacted mass of mix in the can, so thatit may be folded over or otherwise crumpled into position on top of themix. sand is usually added on top of the folded over portion of thelining, and then a seal 7 as molten pitch, is poured on top of the sanduntil it is substantially level with the top of the can. With dry cellsmade as specified it is found that there is considerable troubleexperienced through the corrosion of the zinc immediately below thelayer of sand. The corrosion at this point is much more rapid than inother portions of the cell, and frequently the top portion of the zincwill be entirely separated from the lower portion before the useful lifeof the cell would otherwise have terminated.

It has been found that the excessive corrosion of the zinc near the topis caused by the greater concentration of electrolyte in thisneighborhood, due to the increased amount of electrolyte in thecrumpled-over portion'of the lining. During the action of the cell thesurface of the paper lining adjacent the zinc is depleted of electrolyteand this must be supplied by the diffusion of other electrolyte from theinterior portion of the lining and from the adjacent mix. Since there isa greater mass of the paper lining at the top due to the crumpled-overportion, the electrolyte will diffuse more rap-idly to raise theconcentration of the electrolyte in the surface adjacent the zinc, thanit will in the lower portions of the lining where there is only onethickness of lining. Consequently there results a higher concentrationof electrolyte adjacent the surface of the zinc where the lining isfolded Specification of Letters Patent.

To complete the cell a layer of Patented Feb. 24, 1920.

Application filed May 9, 1919. Serial No. 295,988.

over the top of the mix. The difference in concentration between the topof the zinc and the other portions causes continual electrolytic actionthat eventually dissolves away the zinc at the top.

It has also been found that the excessive corrosion near the top iscaused in part by the good conducting path between the electrode and-thezinc furnished by the bentover portion of the lining which of course ismore or less saturated with good conducting electrolyte. In applying thepaper lining to zinc cans it is usual to use such length of paper orpulpboard'that the ends overlap in a vertical direction. This has beenfound to cause corrosion of the zinc adjacent to this overlappingportion, which is due to theexcess of electrolyte retained by the doublethickness of lining, for substantially the same reason as previouslydescribed in connection with the bent-over portion at the top of themix. My invention aims to overcome these disadvantages and the manner inwhich the result is accomplished will now be described, reference beinghad to the drawings in which:

Figure 1 is a view of a sheet of paper containing my improvement.

Fig. 2 is a section of a battery can wit-h the lining in position.

Fig. 8 is a section taken on the lines AA of Fig. 1, a portion only ofthe lining being shown.

Fig. 4 is a view of a dry cell involving my improvement.

Referring to the drawings, I take a sheet of pulp or other form of paperboard 1 and cut or saturate the topportion 3 and at least one sideportion 2 with some material impervious to electrolyte and moisture,preferably one that is a non-conductor of electricity. Various materialsmay be used, but satisfactory ones are paraflin, tar and petroleum orother suitable oils.

The oils will be particularly serviceable where it is desired tosaturate the edges of the lining instead of applying an outside coating.However, by using such coating materials'as paraffin and tar in hotcondition, the lining edges may be saturated therewithin the same way aswhen oils are used. In Fig. 3 the coating 2 is shown greatly exaggeratedin thickness in relation to the lining 1. It will be understood that thetop portion of the lining 3 will be surrounded or saturated With theinsulating material 4 in the same way as the edge portion 2.

After the linings are coated or impreg nated in the manner specified,they are rolled up and placed inside the zinc can 5 with the edgeportion 3 at the top of the can and the edge 2 overlapping the edge 6,the edge 6 being preferably located adjacent the zinc.

The'inix 7 istampeld inside the lining 1 in any Way, and the saturatedorcoated edge ishent over the top of the mix as shown in, Fig. 4E. Thelayer of sand 8 may be then added and the pitch or other seal 9 pouredon ,topof the sand to complete the cell 7 A jacket is usually added tothe outsideof the zinc can, but this forms no partof the invention andit is not shown on the drawings. I With this construction it Will befound that the corrosion adjacent the pitch seal is no more energeticthan in any other portion of the can. Also the corrosion adjacent totheoverlapped portions 2 and 5 is the same as at any other point on thezinc. Consequently by the treatment of thebibulous lining in the Wayspecified, the life of the cell is very materially increased.

Having described my invention, 'What I claim, is h 1. In dry cells, abibulous lining having a coating of impervious insulating materialadjacent-one edge.

2. In dry cells, a bibulous lining having a coatingor imperviousmaterial on both sides adjacent to one edge andon said edge. 3. In drycells, a bibulous lining having a portion thereof adjacent one edgeimpre nated With insulating material impervious to electrolyte ormoisture. r Y

4. In dry cells, a container electrode having an electrolyte mixtherein, an electrode in said mix, a bibulous lining around the mix withthe side edges overlapping each other, and insulating waterproofmaterial in one of said qvrh ping edges.

5. In dry ce ls, a container electrode having an electrolyte mixtherein, central electrode in said mix, a bibulous lining around themix, said lining having the top edge folded over the top of the mix andWaterproof and insulatingmateiial in the overlapping ortion or saidlining. I

6. In dry cells, a container electrode having an electrolyte inixtherein, a second electrode in said mix, bibulous lining around the mixwith the side edges overlappin ea h other and with the top edge foldedover the mix, and Water-proof and insulating inaterial in one of saidoverlapping edges and in said folded over edge, H

In testimony whereof, I hereunto aflix my signature.

W. HAZELETT.

